This invention relates to the field of integrated circuits packaged in a molded housing. More particularly, this invention relates to a method of improving heat transfer from the integrated circuit chip in molded integrated circuit packages such as surface mounted leaded or leadless chip carriers, dual-in-line packages, and quad flat packages.
This application is related to U.S. Application Ser. No. 07/479,071 entitled Molded Integrated Circuit Package Incorporating Decoupling Capacitor invented by Jorge Hernandez filed contemporaneously with this application.
Molded integrated circuit packages are well known and are available in several commercial configurations including surface mounted leaded or leadless chip carriers, dual-in-line packages and quad flat packages. All of these packages utilize a lead frame which is connected (e.g., wire bonded) to an IC chip; the frame and chip then being encapsulated in a suitable molding material. It will be appreciated that a known problem associated with molded IC packages is the build-up of heat within the package which is generated by the IC chip. Presently, heat is conducted from the IC chip outside the package primarily through the molding material and only partially through the lead frame. However, in certain applications (i.e. very dense, high power IC's), the relatively poor thermal conductivity of the molding compound renders it insufficient for the heat transfer necessary to maintain the correct operation of the IC chip. Because it is difficult for this heat to transfer out of the molded package problems can result in the function and operation of the integrated circuit thereby leading to costly malfunctioning of the electronic device associated with the molded IC package, or making it impossible to encapsulate very dense high power IC's in molded packages. The only viable alternative is to encapsulate them in an expensive ceramic PGA (pin grid array) package. Clearly, it is very desirable to encapsulate high performance, very dense and high power IC's in molded packages which are less costly than their PGA counterparts.